core: move event-emitter to core

Change-Id: I76f6fc7d8c4731bbbb95ea257e339e15b96dbea1
diff --git a/daemon/core/event-emitter.hpp b/daemon/core/event-emitter.hpp
new file mode 100644
index 0000000..b735c20
--- /dev/null
+++ b/daemon/core/event-emitter.hpp
@@ -0,0 +1,325 @@
+/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
+/**
+ * Copyright (C) 2014 Named Data Networking Project
+ * See COPYING for copyright and distribution information.
+ */
+
+#ifndef NFD_CORE_EVENT_EMITTER_HPP
+#define NFD_CORE_EVENT_EMITTER_HPP
+
+#include "common.hpp"
+
+namespace nfd {
+
+struct empty {};
+
+/** \class EventEmitter
+ *  \brief provides a lightweight event system
+ *
+ *  To declare an event:
+ *    EventEmitter<TArgs> m_eventName;
+ *  To subscribe to an event:
+ *    eventSource->m_eventName += eventHandler;
+ *    Multiple functions can subscribe to the same event.
+ *  To trigger an event:
+ *    m_eventName(args);
+ *  To clear event subscriptions:
+ *    m_eventName.clear();
+ */
+
+// four arguments
+template<typename T1 = empty, typename T2 = empty,
+    typename T3 = empty, typename T4 = empty>
+class EventEmitter : noncopyable
+{
+public:
+  /// represents a handler that can subscribe to the event
+  typedef function<void(const T1&, const T2&,
+                               const T3&, const T4&)> Handler;
+  
+  /// adds an subscription
+  void
+  operator+=(Handler handler);
+  
+  /// returns true if there is no subscription,
+  /// otherwise returns false
+  bool
+  isEmpty();
+  
+  /// clears all subscriptions
+  void
+  clear();
+  
+  /// triggers the event
+  void
+  operator()(const T1& a1, const T2& a2, const T3& a3, const T4& a4);
+
+private:
+  /// stores all subscribed handlers
+  std::vector<Handler> m_handlers;
+};
+
+// zero argument
+template<>
+class EventEmitter<empty, empty, empty, empty> : noncopyable
+{
+public:
+  typedef function<void()> Handler;
+  
+  void
+  operator+=(Handler handler);
+
+  bool
+  isEmpty();
+
+  void
+  clear();
+  
+  void
+  operator()();
+
+private:
+  std::vector<Handler> m_handlers;
+};
+
+
+// one argument
+template<typename T1>
+class EventEmitter<T1, empty, empty, empty> : noncopyable
+{
+public:
+  typedef function<void(const T1&)> Handler;
+  
+  void
+  operator+=(Handler handler);
+
+  bool
+  isEmpty();
+
+  void
+  clear();
+  
+  void
+  operator()(const T1& a1);
+
+private:
+  std::vector<Handler> m_handlers;
+};
+
+
+// two arguments
+template<typename T1, typename T2>
+class EventEmitter<T1, T2, empty, empty> : noncopyable
+{
+public:
+  typedef function<void(const T1&, const T2&)> Handler;
+  
+  void
+  operator+=(Handler handler);
+
+  bool
+  isEmpty();
+
+  void
+  clear();
+  
+  void
+  operator()(const T1& a1, const T2& a2);
+
+private:
+  std::vector<Handler> m_handlers;
+};
+
+
+// three arguments
+template<typename T1, typename T2, typename T3>
+class EventEmitter<T1, T2, T3, empty> : noncopyable
+{
+public:
+  typedef function<void(const T1&, const T2&, const T3&)> Handler;
+  
+  void
+  operator+=(Handler handler);
+
+  bool
+  isEmpty();
+
+  void
+  clear();
+  
+  void
+  operator()(const T1& a1, const T2& a2, const T3& a3);
+
+private:
+  std::vector<Handler> m_handlers;
+};
+
+
+// zero argument
+
+inline void
+EventEmitter<empty, empty, empty, empty>::operator+=(Handler handler)
+{
+  m_handlers.push_back(handler);
+}
+
+inline bool
+EventEmitter<empty, empty, empty, empty>::isEmpty()
+{
+  return m_handlers.empty();
+}
+
+inline void
+EventEmitter<empty, empty, empty, empty>::clear()
+{
+  return m_handlers.clear();
+}
+
+inline void
+EventEmitter<empty, empty, empty, empty>::operator()()
+{
+  std::vector<Handler>::iterator it;
+  for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+    (*it)();
+  }
+}
+
+// one argument
+
+template<typename T1>
+inline void
+EventEmitter<T1, empty, empty, empty>::operator+=(Handler handler)
+{
+  m_handlers.push_back(handler);
+}
+
+template<typename T1>
+inline bool
+EventEmitter<T1, empty, empty, empty>::isEmpty()
+{
+  return m_handlers.empty();
+}
+
+template<typename T1>
+inline void
+EventEmitter<T1, empty, empty, empty>::clear()
+{
+  return m_handlers.clear();
+}
+
+template<typename T1>
+inline void
+EventEmitter<T1, empty, empty, empty>::operator()(const T1& a1)
+{
+  typename std::vector<Handler>::iterator it;
+  for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+    (*it)(a1);
+  }
+}
+
+// two arguments
+
+template<typename T1, typename T2>
+inline void
+EventEmitter<T1, T2, empty, empty>::operator+=(Handler handler)
+{
+  m_handlers.push_back(handler);
+}
+
+template<typename T1, typename T2>
+inline bool
+EventEmitter<T1, T2, empty, empty>::isEmpty()
+{
+  return m_handlers.empty();
+}
+
+template<typename T1, typename T2>
+inline void
+EventEmitter<T1, T2, empty, empty>::clear()
+{
+  return m_handlers.clear();
+}
+
+template<typename T1, typename T2>
+inline void
+EventEmitter<T1, T2, empty, empty>::operator()
+    (const T1& a1, const T2& a2)
+{
+  typename std::vector<Handler>::iterator it;
+  for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+    (*it)(a1, a2);
+  }
+}
+
+// three arguments
+
+template<typename T1, typename T2, typename T3>
+inline void
+EventEmitter<T1, T2, T3, empty>::operator+=(Handler handler)
+{
+  m_handlers.push_back(handler);
+}
+
+template<typename T1, typename T2, typename T3>
+inline bool
+EventEmitter<T1, T2, T3, empty>::isEmpty()
+{
+  return m_handlers.empty();
+}
+
+template<typename T1, typename T2, typename T3>
+inline void
+EventEmitter<T1, T2, T3, empty>::clear()
+{
+  return m_handlers.clear();
+}
+
+template<typename T1, typename T2, typename T3>
+inline void
+EventEmitter<T1, T2, T3, empty>::operator()
+    (const T1& a1, const T2& a2, const T3& a3)
+{
+  typename std::vector<Handler>::iterator it;
+  for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+    (*it)(a1, a2, a3);
+  }
+}
+
+// four arguments
+
+template<typename T1, typename T2, typename T3, typename T4>
+inline void
+EventEmitter<T1, T2, T3, T4>::operator+=(Handler handler)
+{
+  m_handlers.push_back(handler);
+}
+
+template<typename T1, typename T2, typename T3, typename T4>
+inline bool
+EventEmitter<T1, T2, T3, T4>::isEmpty()
+{
+  return m_handlers.empty();
+}
+
+template<typename T1, typename T2, typename T3, typename T4>
+inline void
+EventEmitter<T1, T2, T3, T4>::clear()
+{
+  return m_handlers.clear();
+}
+
+template<typename T1, typename T2, typename T3, typename T4>
+inline void
+EventEmitter<T1, T2, T3, T4>::operator()
+    (const T1& a1, const T2& a2, const T3& a3, const T4& a4)
+{
+  typename std::vector<Handler>::iterator it;
+  for (it = m_handlers.begin(); it != m_handlers.end(); ++it) {
+    (*it)(a1, a2, a3, a4);
+  }
+}
+
+
+} // namespace nfd
+
+#endif // NFD_CORE_EVENT_EMITTER_HPP